Brain Primer, Part 1: The Neuroanatomy and Physiology Behind Memory and Aging

Neurodegenerative disease profoundly affects structures and pathways responsible for memory, cognition, and higher-order processing. A foundational understanding of neuroanatomy and physiology is essential for recognizing how these disorders develop and how they are visualized with molecular imaging. Neurons, dendrites, axons, microtubules, and associated proteins, such as tau, form the structural basis for information transmission. Glial cells support neuronal health, regulate neurotransmission, maintain metabolic balance, and contribute to inflammatory responses that become dysregulated with aging. Brain regions such as the hippocampus, amygdala, prefrontal cortex, and limbic system coordinate memory formation, emotional encoding, working memory, and spatial navigation. The physiology of memory relies on encoding, consolidation, storage, and retrieval processes driven by neurotransmitters, such as acetylcholine, glutamate, serotonin, and dopamine. Synaptic plasticity enables adaptive strengthening or weakening of neural connections, whereas age-related changes contribute to natural cognitive decline. This article reviews the neuroanatomy and cellular physiology underlying memory to help understand neurodegenerative patterns and their appearance on advanced imaging.